HAL_CAN_Transmit_IT(): Missing __HAL_UNLOCK() ?

[rs2]

Posted on July 17, 2015 at 11:28

We have experienced EWG error when calling HAL_CAN_Transmit_IT() repeatedly with the same CAN handle.

Making following changes in the hal_can could we solve this problem

HAL_CAN_Transmit_IT(CAN_HandleTypeDef* hcan)

{

   ...

  tmp = hcan->State;

  if((tmp == HAL_CAN_STATE_READY) || (tmp == HAL_CAN_STATE_BUSY_RX))

  {

    __HAL_LOCK(hcan);

    

    /* Select one empty transmit mailbox */

    if((hcan->Instance->TSR&CAN_TSR_TME0) == CAN_TSR_TME0)

    {

      transmitmailbox = 0;

    }

    else if((hcan->Instance->TSR&CAN_TSR_TME1) == CAN_TSR_TME1)

    {

      transmitmailbox = 1;

    }

    else if((hcan->Instance->TSR&CAN_TSR_TME2) == CAN_TSR_TME2)

    {

      transmitmailbox = 2;

    }

    else

    {

      transmitmailbox = CAN_TXSTATUS_NOMAILBOX;

    }

    if(transmitmailbox != CAN_TXSTATUS_NOMAILBOX)

    {

       ....

    }

    /* new code */

    else

    {

        __HAL_UNLOCK(hcan);

        return HAL_BUSY;

    }

    /* end of new code */

    ....

+ Did anyone experienced a similar problem ?

+ HAL should contemplate this case -> STMCubeF4 V1.7  should be fixed ?

Thanks in advance!

#stmcube-stm32f4-can

[rafael7n]

Posted on October 09, 2015 at 20:09

Hello my friend.

I experienced the same problem and also wrote the same solution just before looking for anyone with the same problem.

It makes all sense to me to have this __HAL_UNLOCK(hcan) if no mailbox is empty. It is like a semaphore. In the begin of the function there is a __HAL_LOCK and then a verification on the mailbox to get one that is free. If any of the 3 mailbox is free the function performs the transmission and unlock the semaphore. BUT, if no mailbox is free the semaphore has already being locked and is never unlocked anymore. So a __HAL_UNLOCK(hcan) on the HAL_BUSY part of this function makes complete sense.

I believe it is a bug and should be on the next HAL can module revision.

Best regards

[rs2]

Posted on November 18, 2015 at 13:49

Thank you for your answer!

Yes we think ST will fix this bug.

[Nickname5522_O]

Posted on November 19, 2015 at 16:52

Hi rsp.rsp,

Could you send us your application? So, we can figure out thetestcase.

Thank you

-Shahrzad-

[Nickname5522_O]

Posted on January 25, 2016 at 18:36

Hi,

After investigation, the problem is confirmed and will be fixed in next releases.

-Shahrzad-